Constant impedance coaxial line switch



Sept. 20, 1966 HORTON 3,274,366

CONSTANT IMPEDANCE COAXIAL LINE SWITCH Filed July 27, 1964 5 Sheets-Sheet 1 RUSSELL E. HORTON INVENTOR BY wwafigpmd/ ATTORNEYS Sept. 20, 1966 R. E. HORTON 3,274,366

CONSTANT IMPEDANCE COAXIAL LINE SWITCH Filed July 27, 1964 5 Sheets-Sheet FIG. 4. f

RUSSELL E. HORTON INVENTOR Sept. 20, 1966 E. ORT 3,274,366

CONSTANT IMPEDANCE COAXIAL LINE SWITCH Filed July 27, 1964 3 Sheets-Sheet 5 RUSSELL E. HORTON INVENTOR BY WM ATTORNEYS United States Patent 3,274,366 CONSTANT IMPEDANCE COAXIAL LINE SWITCH Russell E. Horton, Forestville, Conn., assignor to The Bendix Corporation, Farmington, Conn., a corporation of Delaware Filed July 27, 1964, Ser. No. 385,281 6 Claims. (Cl. 200-153) The present invention relates to switches for coaxial transmission lines. More particularly, it relates to an electrically actuated or relay type switch for selectively establishing a circuit between an input coaxial line and several output coaxial lines.

In the various known types of coaxial line relays, provision is made for terminating the outer conductor of the lines to be switched in a common body. Movable contacts are provided within the switch body for interconnecting the inner conductors of the lines in various combinations to establish a desired circuit. The common failing of these types is that the movable interlinking contact element changes position relative to the electrically common wall of the switch body and thus introduces a variation in switch impedance for each of the various switch positions.

It is an object of the present invention to provide a switch for coaxial lines which maintains constant impedance for various switch positions.

Another object of the invention is to provide a switch which by virtue of its constant impedance characteristic provides extended frequency ranges equal to the limits of the transmission lines themselves.

A more specific object of the invention is to provide a constant impedance switch for coaxial lines which is the electrical equivalent of a single pole, double throw switch.

Other objects and advantages of the invention will become apparent as an understanding of its principles is gained through the following detailed description and accompanying drawings.

Briefly, the invention contemplates a switch in which an input coaxial line and alternate output coaxial lines are positioned relative to one another and to movable Contact elements to permit selection of the desired circuit by simple reciprocation of the contact elements. The elements are mounted upon a carrier which is surrounded by a conducting wall. The elements are insulated from both carrier and wall and are movable within the wall in such manner that the spacing between the elements and the wall remains constant regardless of the selected switch position. Impedance variations due to switch movement are thus avoided.

In the drawings:

FIG. 1 is a fragmentary view of the switch illustrating its principle of operation.

FIGS. 2 and 3 are elevation and plan views, respectively, of the invention.

FIG. 4 is a section taken along the line 4-4 of FIG. 3.

FIG. 5 is a perspective of the contact carrier element.

FIG. 6 is an elevation of the contact carrier element.

FIGS. 7 and 8 are sections taken along the lines 77 and 8-8, respectively, of FIG. 6.

Referring to FIGS. 1, the invention is shown as embodied in the equivalent of a single pole, double throw switch. The inner conductors only of the coaxial lines are shown in the fragmentary view of FIG. 1. Line 10 is the switched conductor which may be connected to either of two output lines, the inner conductors of which are 12 and 14. Switching is accomplished by the verti cal reciprocation of contact ring segments 16 and 18. Contacts 16 and 18 are mounted upon an insulated carrier which is omitted from this view for purposes of "ice clarity. The contact carrier is in the form of a piston which works within the switch body 20, shown in phantom. Contacts 16 and 18 are coaxial with the cylindrical body 20 and are maintained in constant spaced relationship by the centering action of the piston-like carrier. The outer conductors of the coaxial lines associated with conductors 10, 12 and 14 all terminate in switch body 20. Thus, regardless of the switch position, whether connecting conductors 10 and 14 by contact 16 as shown, or connecting conductors 10 and 12 by contact 18, the interconnecting contact ring maintains constant spacing fromthe switch body 20 and thus maintains constant impedance regardless of the switch position.

Turning now to the exterior views of the switch, FIGS. 2 and 3, and the sectional view FIG. 4, a practical embodiment of the invention will be described. The coaxial lines to be switched are connected to standard threaded female connectors 11, 13 and 15. These connectors terminate the outer conductors of the coaxial lines in the switch body 20 and lead the inner conductors of the lines to the interior of the switch body. Solenoid housings 17 and 21 contain the electro-mechanical actuator producing reciprocation of contact rings 16 and 18 (FIG. 1). A triangular mounting flange 30 is secured to the upper portion of switch body 20.

Referring particularly to FIG. 4, each of the connectors 11, 13 and 15 include a ferrule 19 which receives the inner conductor of the coaxial line and continues the conductor through the wall of the switch body into the cylindrical cavity of the body. The ferrule 19 is insulated from the outer shell of the connectors and from the body by an insulating bushing 22. Within the switch body the ferrules are terminated in a short length of tightly wound spring 23. The springs 23 are contacted transversely by contact rings 16 and 18 and yield to a slight overtravel of the piston carrying the contact rings to insure positive contact.

As best seen in FIGS. 5 through 8, the carrier piston 24 includes a channel 25 extending at uniform depth along the length of the piston. The open face of channel 25 is assembled facing connector 11 to enable rings 16 and 18 to contact opposite sides of spring 23. Two additional channels 26 and 27, oppositely spaced about the circumference of the piston, extend with uniform depth partially along the length of the piston, ending in abutments 28 and 29. Abutments 28 and 29 are at opposite ends of the piston, and are level with the inner contacting surfaces of rings 16 and 18, to cause grounding of the unused one of the output conductors 12 or 14. With the piston in the upper position, a circuit is established from conductor 10 to 14 by engagement of the upper surface of ring 16 with the spring ends of those conductors. The lower surface of the spring end of conductor 12 then engages abutment 28, grounding that conductor. In the opposite or lower position of the piston, contact is established between conductor 10 and conductor 12 by engagement of the lower surface of ring 18 with the spring ends of those conductors. In the latter position the upper edge of the spring end of conductor 14 engages abutment 29, grounding that conductor. A keyway 39 diametrically opposite channel 25 extends the length of the piston to maintain its alignment during reciprocal motion. Rings 16 and 18 are supported on piston 24 by an insulating compound 32 molded into grooves cut about the circumference of the piston.

Referring particularly to FIG. 4, switch body 20 is provided with top and bottom shoulders 33 supporting top and bottom armature discs 34 and 35. The discs 34 and 35 are spaced sufliciently to permit piston 24 full travel between alternate circuit positions. The discs include facing triangular .slots retaining a trapezoidal key 36 which guides the piston in its movement. Studs 37 and 38, formed integrally with discs 34 and 35, project from the outer faces of the discs to form magnetic poles for the attraction of a movable magnetic slug. Actuating solenoids 39 and 40 are centered about studs 37 and 38 and extend some length beyond them. Magnetic slugs 42 and 43 are freely movable along the axis of the solenoids 39 and 40 and extend substantially the length of the solenoid axis remaining beyond studs 37 .and 38. The studs and slugs are conically faced to provide selfaligning action. Rods 44 and 45, of nonmagnetic material, project inwardly from the ends of slugs 42 and 43, passing through armature discs 34 and 35 to engage the upper .and lower faces of piston 24.

Solenoids 39 and 40 are energized in alternat1on to provide alternate switch positions. Thus, when solenoid 39 is energized stud 37 becomes a magnetic pole strongly attracting slug 42, causing rod 44 to move to its extreme inward position. This, of course, drives piston 24 to its lower contact position in which conductor is connected to conductor 12. The opposite switch position is obtained by energizing solenoid 40. Slug 43 is then strongly attracted to stud 38, moving rod 45 to its extreme inward position and driving piston 24 to its uppermost position, completing the circuit from conductor 10 to conductor 14.

The switch may be maintained in either desired position by means of a spring loaded ball detent 46 operating on rod 45 and a similar detent (not shown) operating on rod 44. The switch may be modified to provide a preferred or normally closed position, with momentary contact in the alternate position, by replacing one of the solenoid operating mechanisms with a spring device. In such a modification, solenoid 40 and slug 43 might be removed and replaced by a coil spring arranged to bias rod 45 continuously upward. A normally closed circuit would then be established between conductor 10 and 14 with contact between conductors 10 and 12 occurring only so long as solenoid 39 is energized.

Other modifications and variations are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically disclosed.

The invention claimed is:

1. A single pole-double throw switch .for coaxial lines comprising:

a hollow switch body,

connectors for an input coaxial line and a pair of output coaxial lines either of which may be selectively connected to said input line, said connectors providing extensions for the inner conductors of said lines to enter said switch body at the same level,

a first contact element within said body at a higher level than said extended inner conductors and overlying the ends of the extensions for said input line and one of said output lines,

a second contact element Within said body at a lower level than said extended inner conductors and underlying the ends of the extensions for said input line and the other of said output lines,

a carrier supporting both of said contact elements with vertical spacing sufiicient for said first contact element to clear said input and said one output ends upon engagement of said second contact element with said input and said other output ends, and

means for vertically reciprocating said carrier to establish alternate connection of said input line to one or the other of said output lines,

2. A single pole-double throw switch for coaxial lines, comprising:

a cylindrical switch body,

coaxial line connectors for extending the inner conductors of an input coaxial line and a pair of output coaxial lines to the interior of said body,

a first ring segment contact within said body and positioned to engage the ends of said input line and one of said output lines,

a second ring segment contact within said body positioned to engage the ends of said input line and the other of said output lines,

a carrier supporting both said first and said second contacts spaced from the inner wall of said body, and

means for moving said carrier to bring said first contact into engagement with the ends of said input line and said one output line and alternately to bring said second contact into engagement with the ends of said input line and said other output line.

3. A switch as claimed in claim 2 wherein said carrier is a piston closely fitting the inner wall of said body.

4. A switch as claimed in claim 3 wherein said means for moving said carrier comprises means for reciprocating said piston.

5. A single pole-double throw switch for coaxial lines, comprising:

a cylindrical switch body,

coaxial line connectors for securing the outer conductors of an input coaxial line and a pair of output coaxial lines to said body, said connectors including means for extending the inner conductors of said output lines to the interior of said body to terminate in oppositely positioned, aligned ends and means for extending the inner conductor of said input coaxial line to the interior of said body to terminate on an axis perpendicular to the axis of the ends of said output lines,

a piston-like contact carrier working in said body, said carrier having a pair of axially spaced grooves extending about its circumference and a channel running parallel to its axis to intersect said grooves,

a pair of ring segment contacts each supported in one of said grooves with an end extending into said channel, said carrier being positioned in said body so that said contact ends in said channel are on opposite sides of the end of said input line,

additional channels in said carrier into each of which one of said output line ends and an end of one of said contacts extend, and

means for reciprocating said carrier to estabilsh a circuit from said input line to alternate ones of said output lines.

6. A switch as claimed in claim 5 wherein said last named means includes a solenoid and a magnetic ele ment driven by said solenoid for applying force to said carrier.

References Cited by the Examiner UNITED STATES PATENTS 2,426,186 8/1947 Dow 200-- 153 X 2,427,940 9/ 1947 Ayres.

- FOREIGN PATENTS 791,123 2/1958 Great Britain. 871,259 6/1961 Great Britain.

ROBERT K. SCHAEFER, Primary Examiner.

KATHLEEN H. CLAFFY, Examiner.

H, HOHAUSER, Assistant Examiner, 

1. A SINGLE POLE-DOUBLE THROW SWITCH FOR COAXIAL LINES COMPRISING: A HOLLOW SWITCH BODY, CONNECTORS FOR AN INPUT COAXIAL LINE AND A PAIR OF OUTPUT COAXIAL LINES EITHER OF WHICH MAY BE SELECTIVELY CONNECTED TO SAID INPUT LINE, SAID CONNECTORS PROVIDING EXTENSIONS FOR THE INNER CONDUCTORS OF SAID LINES TO ENTER SAID SWITCH BODY AT THE SAME LEVEL, A FIRST CONTACT ELEMENT WITHIN SAID BODY AT A HIGHER LEVEL THAN SAID EXTENDED INNER CONDUCTORS AND OVERLYING THE ENDS OF THE EXTENSIONS FOR SAID INPUT LINE AND ONE OF SAID OUTPUT LINES, A SECOND CONTACT ELEMENT WITHIN SAID BODY AT A LOWER LEVEL THAN SAID EXTENDED INNER CONDUCTORS AND UNDERLYING THE ENDS OF THE EXTENSIONS FOR SAID INPUT LINE AND THE OTHER OF SAID OUTPUT LINES, A CARRIER SUPPORTING BOTH OF SAID CONTACT ELEMENTS WITH VERTICAL SPACING SUFFICIENT FOR SAID FIRST CONTACT ELEMENT TO CLEAR SAID INPUT AND SAID ONE OUTPUT ENDS UPON ENGAGEMENT OF SAID SECOND CONTACT ELEMENT WITH SAID INPUT AND SAID OTHER OUTPUT ENDS, AND MEANS FOR VERTICALLY RECIPROCATING SAID CARRIER TO ESTABLISH ALTERNATE CONNECTION OF SAID INPUT LINE TO ONE OR THE OTHER OF SAID OUTPUT LINES. 